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Old 03-08-2005, 11:09 PM
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davidpretorius
lots of eyes on you!

davidpretorius is offline
 
Join Date: Jun 2005
Location: Launceston Tasmania
Posts: 7,381
Motorising the dob - first baby steps.

Hi All,

It is amazing how a hobby can so completely consume your brain.

How to motorize a dob.....here are some initial thoughts!
  • Obviously two axis to be done, RA and DEC
  • Stepper motors controlled by my computer thru the usb port seems a neat way to go if the printer port is taken up by long exposure software. I should be able to drive four motors with stepper motor controller ie RA, DEC, the focuser and.....spoon to stir coffee.
  • Where to drive DEC axis? - at the pivot point or with rails on bottom of tube.
  • Question 1: at maximum magnification, what would the angle of the normal field of view be? say at 6mm ep with 2X or 3X or even 5X. I want to know how fine in terms of degrees i need to be to be so i can get fine movements ie .1 of a degree. I may have to gear it!
  • Question 2: Assuming everything works in driving accurately, getting the computer to adjust for the rotation of the earth should be possible. ie point at a know location, calibrate the machine and of you go. Do anyone know of references for calculating the drift at different spaces from the celestrial equator?
I have on purpose not searched on the internet just yet, and I know lots of people have probabley tried this already. I am enjoying the mental exercise dreaming up stuff. It may not be useful and feel like reinventing the wheel, but it is fun.
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